1. Technical Field
The present invention relates to a display device, such as an organic EL display device or the like that is mounted on a movable body of a vehicle such as an automobile, an airplane, a ship, a streetcar or the like and that displays a speed of a movable body, an engine speed, geographical information of a car navigation device or the like, and to a display module of the movable body.
2. Related Art
In recent years, an organic EL panel using an organic electroluminescent (hereinafter, referred to as ‘EL’) element has attracted attention because it is superior than other devices in low power consumption, a wide viewing angle, and a high contrast ratio. An example of the organic EL display device using the organic EL panel has been disclosed (for example, JP-A-2004-127924).
In addition, as an example of an information display device for a vehicle which is mounted on an instrument panel of a vehicle such as an automobile or the like, an information display device in which a plurality of display is performed on one screen composed of a liquid crystal display device (multi-display device) has been known (for example, see JP-A-2004-291731). In such an information display device for a vehicle, one liquid crystal panel is used. In the liquid crystal panel, three kinds of display is performed by means of a first display unit serving as a speedometer for displaying a speed, a second display unit serving as a tachometer for displaying an engine speed, and a third display unit for displaying geographical information of a car navigation device.
However, in the organic EL display device according to the related art disclosed in JP-A-2004-127924, three kinds of organic EL elements for R, G, and B (organic EL elements for red, green, and blue) disposed in a matrix are different from one another in thermal deterioration and thermal stability. For example, a material of each of the organic EL elements for red and green is vulnerable to the heat (temperature dependency of characteristic deterioration is high), but a material of the organic EL element for blue is not deteriorated even when the temperature becomes high.
In a case in which this organic EL display device is mounted on an instrument panel of a vehicle such as an automobile or the like and various vehicle information such as a vehicle speed and an engine speed or the like is displayed on the organic EL panel, if the temperature of the organic EL panel becomes high, the life span of each of the organic EL elements becomes shortened. In the vehicle such as the automobile or the like, it is required that each of organic EL elements of the organic EL panel should emit light normally even when the indoor temperature of the vehicle or the temperature of the organic EL panel is about 85° C. For this reason, when the organic EL panel becomes a high temperature, a countermeasure needs to be arranged in order to prevent the life span of each organic EL panel from being shortened. In addition, in a gauge board of a movable body, for example, an instrument panel of a vehicle such as an automobile or the like, various indicators can perform only limited types of display.